1. Field of the Invention
The invention relates to a time adjustment method in a telecommunication system, a time stamping method in a telecommunication system, and a telecommunication system.
2. Description of the Related Art
In modern telecommunication systems, timing and time stamping of signals transmitted from a base station in a telecommunication system can be used, for example, for synchronization and positioning purposes.
In a prior art time stamping process, the transmission time of a signal transmitted from the base station is determined by using the time point of generating the signal in the base band parts of the transmitter of the base station, and possibly information on the delay between generating the signal in the base band parts and transmitting the signal from an antenna unit of the base station. This delay is caused by electric components and wires in between the base band part and the antenna unit.
The prior art solutions in time characterization of signals transmitted from the base station, however, are insufficient in accuracy to fulfill the tightened requirements of time characterization. The insufficiency arises from unpredictable nature of the electronics in radio transmitters, giving rise to unpredictable variation in the propagation time of a signal between the base band parts and the antenna of the base station. The insufficiency in accuracy of the time characterization causes, for example, inaccuracy in measuring the propagation time of a signal between the base station and a mobile station, giving rise to errors in location information of the mobile station.
Therefore, it is desirable to consider improved tools for time stamping and time adjustment.